Long reply with an update.
In addition to the helpful non-veterinary suggestions on this thread (many of which I had already tried/was already doing), there were suggestions to explore PSSM. That was very helpful.
She seems ambivalent to girth type (including the tapestry girthāI was never able to find the alleged horror stories about the girth and she reacted no differently to it than any other girth). She had lost some topline and I had my saddle reflocked. She seems about the same with a back warmed first by a BOT or other product. She doesnāt dislike this but I didnāt see a noticeable difference.
Lunging, slow walking warmup first, slow progression of tightening the girth, really good grooming over the back before riding, going slow with grooming and tacking, walking in hand before getting on, suppling exercises at the walkāI had tried/still do all of these things and none of them seem to make a significant difference.
Okay so on to that PSSM suggestion which was so helpfulā¦
She tested negative for Type 1 by genetic test (no huge surprise there given that sheās a WB). After a few false starts getting the PSSM Type 2 genetic test done, I got the results back yesterday. She is heterozygous positive for the P2 PSSM2 gene mutation, homozygous for the P8 PSSM2 gene mutation, and homozygous for the PxRER gene mutation. There is some controversy over the reliability of this genetic testing, but the more definitive diagnosis is via muscle biopsy and I am not inclined to put her through that until I try the diet first (and Iād rather do it after fly season anyway because it involves remove a big chunk of flesh which then has to heal).
I had bloodwork drawn for allergy testing while working up the PSSM, and she has some food allergies, including most notably corn, soy, oats, and flax. Sheās starting allergy shots, but those primarily target non-food allergies so itās best to try to eliminate food allergens from the diet entirely (this would be my 3rd horse tested for allergies that came back with some significant food allergies so I have been down the allergy road many times before).
Iāve started switching her over to PSSM Type 2 diet.
Full lameness workup, again very sound.
I also did a CBC and Lyme test and she was not deficient in anything (including Vitamin E) or positive for Lyme. But I did those too because I thought those were good to rule out the other very appropriate suggestions for possible explanations. She had another set of x-rays done and they look as pristine and perfect as the firstāno kissing spines. She did have resting and post-exercise CK tested and it elevated post exercise so thereās another anecdotal piece of data to suggest PSSM Type 2. Again, not definative-- but enough to make me think I should try the diet.
I didnāt scope her because I wanted to try one thing at a time and once I hit on PSSM Type 2 being a likely culprit I wanted to try the diet first. But if the diet doesnāt work, scoping will be on the list.
